[Two operative cases of quadricuspid aortic valve].

We report two cases of rare congenital anomaly of quadricuspid aortic valve. Case 1, an 81-year-old man was operated on because of aortic regurgitation without diagnosis of a quadricuspid aortic valve. He underwent aortic valve replacement with a 21 mm Hancock-II successfully. Case 2, a 40-year-old woman suffering from aortic regurgitation was diagnosed as quadricuspid aortic valve, before surgery using echocardiography and aortography. She underwent aortic valve replacement with a 21 mm H-P St. Jude Medical prosthesis successfully. Both cases were regarded as type c (2 equal larger cusps, 2 equal smaller cusps) by Hurwitz's classification. Thirty cases of quadricuspid aortic valve are reviewed in the Japanese literature including our two cases. All cases underwent aortic valve replacement because of aortic regurgitation. In 19 cases, it was possible to diagnose that those valves were quadricuspid before surgery, using echocardiography and aortography. In conclusion, it is necessary to take quadricuspid aortic valve into consideration in the case of aortic regurgitation.